/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/**

 * Defines the {@link com.bff.gaia.unified.sdk.transforms.windowing.Window} transform for dividing the

 * elements in a PCollection into windows, and the {@link

 * com.bff.gaia.unified.sdk.transforms.windowing.Trigger} for controlling when those elements are output.

 *

 * <p>{@code Window} logically divides up or groups the elements of a {@link

 * com.bff.gaia.unified.sdk.values.PCollection} into finite windows according to a {@link

 * com.bff.gaia.unified.sdk.transforms.windowing.WindowFn}. The output of {@code Window} contains the

 * same elements as input, but they have been logically assigned to windows. The next {@link

 * com.bff.gaia.unified.sdk.transforms.GroupByKey}s, including one within composite transforms, will

 * group by the combination of keys and windows.

 *

 * <p>Windowing a {@code PCollection} allows chunks of it to be processed individually, before the

 * entire {@code PCollection} is available. This is especially important for {@code PCollection}s

 * with unbounded size, since the full {@code PCollection} is never available at once.

 *

 * <p>For {@code PCollection}s with a bounded size, by default, all data is implicitly in a single

 * window, and this replicates conventional batch mode. However, windowing can still be a convenient

 * way to express time-sliced algorithms over bounded {@code PCollection}s.

 *

 * <p>As elements are assigned to a window, they are are placed into a pane. When the trigger fires

 * all of the elements in the current pane are output.

 *

 * <p>The {@link com.bff.gaia.unified.sdk.transforms.windowing.DefaultTrigger} will output a window when

 * the system watermark passes the end of the window. See {@link

 * com.bff.gaia.unified.sdk.transforms.windowing.AfterWatermark} for details on the watermark.

 */

@DefaultAnnotation(NonNull.class)

package com.bff.gaia.unified.sdk.transforms.windowing;



import edu.umd.cs.findbugs.annotations.DefaultAnnotation;

import edu.umd.cs.findbugs.annotations.NonNull;